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Author: Ahmed G. Tukur Publisher: ISBN: Category : Demand controlled ventilation systems Languages : en Pages : 80
Book Description
Variable Air Volume (VAV) systems are the most popular HVAC systems in commercial buildings. VAV systems are designed to deliver airflows at design conditions which only occur for a few hours in a year. Minimizing energy use in VAV systems requires reducing the amount of airflow delivered through the system at part load conditions. Air Handling Unit (AHU) fans are the major drivers of airflow in VAV systems and installing a Variable Frequency Drive (VFD) is the most common method of regulating airflow in VAV systems. A VFD drive does not necessarily save energy without use of an appropriate control strategy. Static pressure reset (SPR) is considered to be the most energy efficient control strategy for AHU fans with VFDs installed. The implementation of SPR however has many challenges; for example, rogue zones--zones which have faulty sensors or failed controls and actuators, system dynamics like hunting and system diversity. By investigating the parameters associated with the implementation of SPR in VAV systems, a new, improved, more stable SPR algorithm was developed and validated. This approach was further improved using Fault Detection and Diagnostics (FDD) to eliminate rogue zones. Additionally, a CO2 Demand Control Ventilation (DCV) based minimum airflow control was used to further reduce ventilation airflow and save more energy from SPR. Energy savings ranging from 25% to 51% were recorded in actual buildings with the new SPR algorithm. Finally, a methodology that utilizes historical VAV data was developed to estimate the potential savings that could be realized using SPR. The approach employed first determines an effective system loss coefficient as a function of mean damper position using the historical duct static pressure, VAV damper positions and airflows. Additionally, the historical data is used to identify the maximum mean duct damper position realizable as a result of insuring a sufficient number of VAVs are fully open at any time. Savings are estimated by shifting the damper distribution mean at each time to this maximum value and reducing the static pressure to achieve the same overall system airflow rate. The methodology was tested on three different buildings with varying system characteristics. Savings estimates correlated well to the savings actually realized from SPR. This result has significant implications for energy service providers, who could use the predictions to guarantee savings from SPR.
Author: Ahmed G. Tukur Publisher: ISBN: Category : Demand controlled ventilation systems Languages : en Pages : 80
Book Description
Variable Air Volume (VAV) systems are the most popular HVAC systems in commercial buildings. VAV systems are designed to deliver airflows at design conditions which only occur for a few hours in a year. Minimizing energy use in VAV systems requires reducing the amount of airflow delivered through the system at part load conditions. Air Handling Unit (AHU) fans are the major drivers of airflow in VAV systems and installing a Variable Frequency Drive (VFD) is the most common method of regulating airflow in VAV systems. A VFD drive does not necessarily save energy without use of an appropriate control strategy. Static pressure reset (SPR) is considered to be the most energy efficient control strategy for AHU fans with VFDs installed. The implementation of SPR however has many challenges; for example, rogue zones--zones which have faulty sensors or failed controls and actuators, system dynamics like hunting and system diversity. By investigating the parameters associated with the implementation of SPR in VAV systems, a new, improved, more stable SPR algorithm was developed and validated. This approach was further improved using Fault Detection and Diagnostics (FDD) to eliminate rogue zones. Additionally, a CO2 Demand Control Ventilation (DCV) based minimum airflow control was used to further reduce ventilation airflow and save more energy from SPR. Energy savings ranging from 25% to 51% were recorded in actual buildings with the new SPR algorithm. Finally, a methodology that utilizes historical VAV data was developed to estimate the potential savings that could be realized using SPR. The approach employed first determines an effective system loss coefficient as a function of mean damper position using the historical duct static pressure, VAV damper positions and airflows. Additionally, the historical data is used to identify the maximum mean duct damper position realizable as a result of insuring a sufficient number of VAVs are fully open at any time. Savings are estimated by shifting the damper distribution mean at each time to this maximum value and reducing the static pressure to achieve the same overall system airflow rate. The methodology was tested on three different buildings with varying system characteristics. Savings estimates correlated well to the savings actually realized from SPR. This result has significant implications for energy service providers, who could use the predictions to guarantee savings from SPR.
Author: Charles Nehme Publisher: Charles Nehme ISBN: Category : Technology & Engineering Languages : en Pages : 88
Book Description
Preface: Navigating the World of Variable Air Volume (VAV) Systems Welcome to the fascinating world of Variable Air Volume (VAV) systems, where the art and science of HVAC (Heating, Ventilation, and Air Conditioning) converge to create efficient, comfortable, and environmentally friendly indoor environments. If you've ever wondered how modern buildings manage to maintain just the right temperature, humidity, and air quality while minimizing energy consumption, you're about to embark on a journey of discovery. In today's rapidly changing world, energy efficiency and sustainability have become paramount concerns. Whether you're an HVAC professional seeking to deepen your knowledge, a building owner aiming to optimize your facility's performance, or simply a curious individual eager to understand the systems behind your daily comfort, this book is your gateway to mastering VAV systems. **Unveiling the Complexity Behind the Comfort** Variable Air Volume (VAV) systems are the hidden heroes of climate control. They are the intelligent, adaptable systems responsible for regulating the air we breathe in offices, hospitals, shopping malls, and countless other spaces. Yet, these systems often operate unnoticed, silently adjusting airflow and temperature to create a pleasant, productive environment. This book takes you behind the scenes, unraveling the complexity of VAV systems and revealing the inner workings of the technology that has transformed the way we experience indoor comfort. From the fundamentals of HVAC to the intricate design and control strategies of VAV systems, you'll gain a deep understanding of how these systems contribute to energy savings, enhanced comfort, and a greener planet. **Your Guide to VAV Mastery** Our journey begins with the basics, ensuring that everyone, regardless of their prior knowledge, can grasp the core concepts. We'll explore the components of VAV systems, discuss their benefits, and delve into the design and installation processes. You'll learn how to troubleshoot common issues, conduct maintenance, and even retrofit existing systems for greater efficiency. But this book doesn't stop at the basics. We'll explore advanced topics such as energy-efficient practices, sustainable design principles, and the integration of VAV systems into smart buildings. You'll gain insights into real-world applications across various sectors, from commercial buildings to healthcare facilities, all while keeping an eye on future trends and innovations that promise to shape the HVAC landscape. **Empowering You with Knowledge** Our aim is to empower you with knowledge that will not only help you excel in your professional pursuits but also make informed decisions about the indoor environments you inhabit. By the time you reach the last page, you'll be equipped to optimize VAV systems, reduce energy consumption, and contribute to a more sustainable future. As you embark on this educational journey, keep in mind that VAV systems are not just about engineering and technology; they're about enhancing the quality of life for people in buildings all around the world. I hope you find this book informative, engaging, and inspiring, and I encourage you to apply the knowledge you gain here to make a positive impact on the spaces we live and work in. Let's venture forth into the world of Variable Air Volume (VAV) systems, where innovation meets comfort, and where we discover the limitless potential of efficient HVAC solutions. Best regards, Charles Nehme HVAC Q & A What is HVAC? HVAC stands for heating, ventilation, and air conditioning. It is a system of technology that controls the temperature, humidity, and ventilation of indoor and restricted spaces. How does HVAC work? HVAC systems typically use a combination of heating and cooling elements, fans, and ductwork to control the indoor environment. The specific components and operation of an HVAC system will vary depending on the type of system and the specific needs of the building. What are the different types of HVAC systems? There are many different types of HVAC systems, but some of the most common include: * Central heating and cooling systems * Split systems * Ductless mini-split systems * Heat pumps * Furnaces * Air conditioners How do I choose the right HVAC system for my home? When choosing an HVAC system for your home, there are a number of factors to consider, such as the size of your home, the climate you live in, your budget, and your energy efficiency goals. It is important to consult with a qualified HVAC professional to get the best advice for your specific needs. What is the best way to maintain my HVAC system? The best way to maintain your HVAC system is to have it inspected and serviced by a qualified professional on a regular basis. This will help to ensure that your system is operating efficiently and safely. You should also change your air filter regularly, according to the manufacturer's recommendations. Short answer: HVAC stands for heating, ventilation, and air conditioning. It is a system of technology that controls the temperature, humidity, and ventilation of indoor and restricted spaces. There are many different types of HVAC systems, and the best way to choose the right one for your home is to consult with a qualified HVAC professional. To maintain your HVAC system, have it inspected and serviced by a qualified professional on a regular basis and change your air filter regularly.
Author: Raj P. Chhabra Publisher: CRC Press ISBN: 149871529X Category : Science Languages : en Pages : 1649
Book Description
The CRC Handbook of Thermal Engineering, Second Edition, is a fully updated version of this respected reference work, with chapters written by leading experts. Its first part covers basic concepts, equations and principles of thermodynamics, heat transfer, and fluid dynamics. Following that is detailed coverage of major application areas, such as bioengineering, energy-efficient building systems, traditional and renewable energy sources, food processing, and aerospace heat transfer topics. The latest numerical and computational tools, microscale and nanoscale engineering, and new complex-structured materials are also presented. Designed for easy reference, this new edition is a must-have volume for engineers and researchers around the globe.
Author: Simon Winata Publisher: ISBN: Category : Languages : en Pages : 364
Book Description
This study investigated building energy consumption mainly on the HVAC system supply fan energy consumption and building reheat energy. HVAC system for a building often operates using either Constant Air Vo1ume (CAV) system or Variable Air Volume (VAV) system. The CAV system supplies a constant amount of air into each zone by varying the supply air temperature. On the other hand the VAV system operates by responding to each zone's load requirements by varying the air flow rate through a combination of pressure controls and VAV damper position. A VAV system can be operated by utilizing a variable speed drive fan to achieve optimum saving. There are several techniques that can be applied to control the supply fan speed; two of which were being compared in the study. One technique that is commonly used is constant static pressure control. The supply fan is controlled to maintain a constant static pressure at an arbitrary point in the duct system. Another technique is called Terminal Responsive Static Pressure (TRSP) control which gradually decrease or increase the duct static pressure set-point according to the system's needs. As mentioned above the second part of the study focused on the system reheat energy. There are many systems that can be used to meet the heating load of a building. These include perimeter base board heater using either electric or hydronic system, terminal reheat (electric or hydronic), dual duct system, and others. This research investigated the advantages and disadvantages of hydronic and electric terminal reheat by doing energy simulation with DOE-2 and performing economic analysis on both systems.
Author: Herbert W. Stanford III Publisher: CRC Press ISBN: 0429890869 Category : Science Languages : en Pages : 460
Book Description
Analysis and Design of Heating, Ventilating, and Air-Conditioning Systems, Second Edition, provides a thorough and modern overview of HVAC for commercial and industrial buildings, emphasizing energy efficiency. This text combines coverage of heating and air conditioning systems design with detailed information on the latest controls technologies. It also addresses the art of HVAC design along with carefully explained scientific and technical content, reflecting the extensive experience of the authors. Modern HVAC topics are addressed, including sustainability, IAQ, water treatment and risk management, vibration and noise mitigation, and maintainability from a practical point of view.
Author: Wenshu Fan Publisher: ISBN: Category : Languages : en Pages :
Book Description
In a single duct variable air volume (SDVAV) system, the supply air temperature is usually set as a constant value. Since this constant setpoint is selected to satisfy the maximum cooling load conditions, significant reheat will occur once the airflow reaches the minimum and the heating load increases. Resetting the supply air temperature (SAT) higher during the heating season can reduce the reheat. However, air flow will increase when the SAT is higher which consume extra fan power. Therefore, to minimize the total operating cost of a SDVAV system, the supply air temperature is typically reset based on outside air temperature (OAT) with a linear reset schedule. However, the linear reset schedule is often determined based on the engineer's experience and it may not represent the optimal reset schedule for each building. This thesis documents a study to determine the optimized supply air temperature reset schedule for SDVAV systems and analyzes the influencing factors under different operation scenarios. The study was divided into five main sections. The first section introduces the research background and objective. Literature review is documented after the introduction. The third section describes the methodology used in this study and the fourth section develops an in-depth discussion and analysis of the impact of the key influencing factors: minimum air flow ratio; ratio of exterior zone area to total floor area (i.e., exterior area ratio); internal load and the prices of the electricity; the cooling and the heating energy. The simulation results using EnergyPlus Version 2.1.0 for various operation scenarios are investigated in this section. The last section is a conclusion of the whole study. The optimized supply air temperature can be set with respect to the OAT. The study found that instead of a simple linear relationship, the optimal reset schedule has several distinctive segments. Moreover, it is found that the optimal supply air temperature reset schedule should be modified with the change of operation conditions (e.g., different minimum flow ratios and internal loads). Minimum air flow ratio has a significant impact on energy consumption in a SDVAV system. Exterior area ratio determines zone load distribution and will change system load indirectly. For buildings with small internal load, a more aggressive supply air temperature reset tactic can be implemented. In addition, the cost of electricity, cooling and heating energy can determine which end use energy (i.e., reheat energy and fan power) should take the priority.
Author: Xin Zhang Publisher: Springer Nature ISBN: 9811970912 Category : Architecture Languages : en Pages : 167
Book Description
This book presents a systematic study on the air balancing technologies in heating, ventilation and air conditioning (HVAC) systems. Several modern air balancing methods, including advanced control-based air balancing, data-driven-based air balancing, and energy-saving-oriented air balancing, are introduced in this book to balance the air duct system. Furthermore, this book provides clear instructions for both HVAC designers and engineers, as well as researchers, on how to design and balance duct systems for improved performance and energy efficiency.
Author: Steve Doty Publisher: The Fairmont Press, Inc. ISBN: 0881736481 Category : Business & Economics Languages : en Pages : 718
Book Description
"Updated and expanded, this edition includes new material on early replacement business justification, lease arrangements and effect on ECM project interest, coordinating upstream/downstream set points, semiconductor fab multi-stage HVAC air tempering, commissioning, HVAC overlapping heating and cooling, and much more. The book begins with the premise that when commercial facilities are subdivided into categories based on business type, many useful patterns can be identified that become generally applicable to the performance of an effective energy audit. The author discusses procedures and guidelines for a wide range of business and building types, such as schools and colleges, restaurants and fast food, hospitals and medical facilities, grocery stores, laboratories, lodging, apartment and office buildings, retail, public safety, data centers, churches and religious facilities, libraries, laundries, and warehouses. He also covers all focal areas of the building energy audit and assessment, including building envelope, lighting, HVAC, controls, heat recovery, thermal storage, electrical systems, and utilities." -- Publisher.
Author: Ahmed G. Tukur
Author: Ahmed G. Tukur
Author: Charles Nehme
Author: Guang Qu
Author: Raj P. Chhabra
Author: Simon Winata
Author: Leo A. Meyer
Author: Herbert W. Stanford III
Author: Wenshu Fan
Author: Xin Zhang
Author: Steve Doty